Herbicidal N-triazolylmethyl-substituted alpha-haloacetanilide

ABSTRACT

Compounds of the formula ##STR1## wherein Ar is aryl, R 1  is halomethyl, R 2  is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, alkoxy, haloalkyl, alkylthio, alkenylthio, alkynylthio, aryl or NR 5  R 6  wherein R 5  and R 6  individually are hydrogen, alkyl, alkenyl or alkynyl, R 3  is hydrogen or alkyl, n is 1 or 2, Y is O, S or NR wherein R is hydrogen, alkyl, alkenyl or alkynyl, have been found to be useful herbicides.

DESCRIPTION OF THE PRIOR ART

U.S. Pat. No. 3,901,917, issued Aug. 26, 1975 to S. B. Richter,discloses herbicidal N-thienylalkylacetanilides.

U.S. Pat. No. 3,819,661, issued June 25, 1974 to L. L. Maravetz,discloses herbicidal 2-chloro-N-furfuryl ortetrahydrofurfurylacetanilides.

U.S. Pat. No. 3,907,544, issued Sept. 23, 1975 to J. F. Olin, disclosesherbicidal 2-halo-N-(cyclicimidoalkylene)-substituted acetanilides.

U.S. Pat. Nos. 3,859,308, 3,888,882 and 3,946,046, issued to S. B.Richter, disclose N-alpha-haloacetyl-N-(1,3-dioxan-2-yl-alkyl)anilides.

DESCRIPTION OF THE INVENTION

The compounds of the invention are represented by the formula ##STR2##wherein Ar is phenyl or phenyl substituted with 1 to 3 of the same ordifferent substituents selected from fluoro, chloro, bromo, iodo, alkylof 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms or haloalkyl of 1to 4 carbon atoms and 1 to 3 of the same or different halogens selectedfrom fluoro, chloro, bromo or iodo, R¹ is halomethyl of 1 to 3 of thesame or different halogens selected from fluoro, chloro, bromo, or iodo,R₂ is hydrogen; alkyl of 1 to 6 carbon atoms; alkenyl of 2 to 6 carbonatoms; alkynyl of 2 to 6 carbon atoms; cycloalkyl of 3 to 6 carbonatoms; haloalkyl of 1 to 4 carbon atoms and 1 to 3 of the same ordifferent halogens selected from fluoro, chloro, bromo or iodo; alkoxyof 1 to 6 carbon atoms; alkylthio of 1 to 6 carbon atoms; alkenylthio of2 to 6 carbon atoms; alkynylthio of 2 to 6 carbon atoms; phenyl; phenylsubstituted with 1 to 3 of the same or different substituents selectedfrom fluoro, chloro, bromo, iodo, alkyl of 1 to 4 carbon atoms, alkoxyof 1 to 4 carbon atoms or haloalkyl of 1 to 4 carbon atoms and of 1 to 3of the same or different halogens selected from fluoro, chloro, bromo oriodo; or NR⁵ R⁶ wherein R⁵ and R⁶ individually are hydrogen, alkyl of 1to 6 carbon atoms, alkenyl of 2 to 6 carbon atoms or alkynyl of 2 to 6carbon atoms, R³ is hydrogen or alkyl of 1 to 6 carbon atoms, n is 1 or2, and Y is O, S or NR wherein R is hydrogen, alkyl of 1 to 6 carbonatoms, alkenyl of 2 to 6 carbon atoms or alkynyl of 2 to 6 carbon atoms.

Representative substituted-phenyl groups which Ar and R² may representare 2-fluorophenyl, 2,4-dichlorophenyl, 3,5-dibromophenyl, 4-iodophenyl,4-methylphenyl, 2,6-diethylphenyl, 4-trifluoromethylphenyl,2-methoxyphenyl, 2,6-dimethyl-4-chlorophenyl, 2,3,5-trimethylphenyl,2,3,5,6-tetramethylphenyl. Preferred substituted-phenyl Ar groups arephenyl substituted with 1 to 2 of the same or different substituentsselected from fluoro, chloro, bromo, alkyl of 1 to 4 carbon atoms oralkoxy of 1 to 4 carbon atoms.

Representative halomethyl groups which R¹ may represent includefluoromethyl, chloromethyl, bromomethyl, iodomethyl, dichloromethyl,tribromomethyl and fluorodichloromethyl.

Representative alkyl R, R², R³, R⁵ and R⁶ groups are methyl, ethyl,isopropyl and n-hexyl.

Representative alkenyl R, R², R⁵ and R⁶ groups include vinyl, allyl,2-butenyl and 3-hexenyl. Representative alkynyl R, R², R⁵ and R⁶ groupsare propargyl, 2-butynyl, 1-butynyl and 5-hexynyl. Representativecycloalkyl R² groups are cyclopropyl, 2-methylcyclopentyl andcyclohexyl. Representative haloalkyl R² groups are chloromethyl,3-bromopropyl, 2,2-dichloroethyl and trichloromethyl. Representativealkylthio, alkenylthio, alkynylthio R² groups are methylthio, ethylthio,isopropylthio, vinylthio, allylthio and propargylthio. Representativealkoxy R² groups are methoxy, ethoxy and n-propoxy.

Representative NR groups are amino, alkylamino, alkenylamino andalkynylamino such as methylamino, ethylamino, isopropylamino,n-hexylamino, allylamino, propargylamino, etc. Representative NR⁵ R⁶groups are amino, methylamino, allylamino, propargylamino,dimethylamino, diethylamino, N-allyl-N-methylamino, etc.

Preferably Ar is phenyl substituted with 1 to 3 substituents selectedfrom fluoro, chloro, bromo or alkyl of 1 to 3 carbon atoms. Mostpreferably Ar is phenyl substituted with substituents at the 2- and the6-positions, especially 2,6-dialkylphenyl.

Preferably R¹ is monohalomethyl, especially chloromethyl or bromomethyl.

Preferably R² is hydrogen, alkyl of 1 to 3 carbon atoms, phenyl orphenyl substituted with 1 to 3 fluoro, chloro, bromo or alkyl of 1 to 3carbon atoms. Most preferably R² is hydrogen or alkyl of 1 to 3 carbonatoms.

Preferably Y is O or NR wherein R is hydrogen or alkyl of 1 to 3 carbonatoms, and preferably n is 1.

A preferred class of compounds represented by formula (I) is thatwherein Ar is 2,6-dialkylphenyl, R¹ is chloromethyl or bromomethyl, R²is hydrogen or alkyl of 1 to 6 carbon atoms, Y is oxygen and n is 1.

Another preferred class of compounds represented by formula (I) is thatwherein Ar is 2,6-dialkylphenyl, R¹ is chloromethyl or bromomethyl, R²is hydrogen or alkyl of 1 to 6 carbon atoms, Y is NR wherein R ishydrogen, alkyl of 1 to 3 carbon atoms or alkenyl of 2 to 6 carbon atomsand n is 1. In this class, R² most preferably is alkyl and Y mostpreferably is NH.

The compounds of the invention are prepared by acylating an oxadiazole,thiadiazole or triazole (II) with an acyl halide (III), as depicted bythe following reaction (1): ##STR3## wherein Ar, R¹, R², R³, Y and nhave the same meaning as previously defined, and X is chloro or bromo.

The acylation reaction (1) is conducted by conventional procedures,preferably in the presence of an organic amine such as a trialkyl amineor a pyridine compound to scavenge the hydrogen halide by-product. Thereactants (II) and (III) and the amine are generally contacted insubstantially equimolar amounts in an inert organic solvent at atemperature of 0° to 100° C. Suitable inert organic solvents includeethyl acetate, dichloromethane, dimethoxyethane, benzene, etc. Theproduce (I) is isolated and purified by conventional procedues such asextraction, distillation, chromatography, crystallization, etc.

The oxadiazole intermediate of formula (II) (Y═O) is prepared by thecyclization reaction of a hydrazide (IV) and an imidate.hydrochloride(V) under basic reaction conditions, as depicted in the followingreaction (2): ##STR4## wherein R², R³, Ar and n have the same meaning aspreviously defined, and R⁴ is lower alkyl of 1 to 3 carbon atoms.

Generally, reaction (2) is conducted by reacting substantially equimolaramounts of the hydrazide (IV), the imidate (V) and an organic base, suchas a pyridine compound, in the liquid phase at a temperature of 25° to150° C. In one modification of the reaction, excess of the organic base,i.e., pyridine, is used as solvent. Other suitable organic solvents forthe reaction include chlorinated hydrocarbons, e.g., dichloromethane,and aromatic compounds, e.g., toluene and chlorobenzene. The product isisolated and purified by conventional procedures such as extraction,distillation, chromatography, crystallization, etc.

The triazole intermediate of formula (II) (Y═NH) is prepared by thecyclization reaction of a hydrazide (IV) and an amidine (VI) under basicreaction conditions, as depicted in reaction (3): ##STR5## wherein R²,R³, Ar and n have the same meaning as previously defined. It isappreciated, of course, that the triazole ring of formula (II) may existin other tautomeric forms.

The cyclization reaction (3) is conducted in the presence of a base.Suitable bases are inorganic alkali metal hydroxdes such as sodiumhydroxide and potassium hydroxide. Generally, substantially molaramounts of reactants (IV) and (VI) and the base are employed.Preferably, however, a small excess of the base is employed, e.g., themolar ratio of base to hydrazide is preferably from 1.2:1 to 1.1:1. Thereaction is conducted in the liquid phase in organic solvents. When aninorganic alkali metal hydroxide is employed as the base, alkanols,e.g., methanol, in which the hydroxide is partially soluble arepreferably employed as the solvent. Reaction temperatures generally varyfrom 25° C. to 150° C. The product (II) is generally purified byconventional procedures, e.g., extraction, distillation orcrystallization, before use in the acylation reaction (1).

The triazole intermediates of formula (II) (Y═NH) may also be preparedby the reaction of the hydrazide (IV) and the imidate (V) in the liquidphase under neutral reaction conditions as depicted in reaction (4):##STR6## wherein R², R³, R⁴, Ar and n have the same significance aspreviously defined.

Reaction (4) is carried out under substantially the same reactionconditions as reaction (2), except no base is employed. For example,generally substantially equimolar amounts of the reactants (IV) and (V)are reacted in an inert organic solvent at a temperature of from 25° C.to 150° C., preferably 50° C. to 150° C.

The hydrazide intermediate (IV) is prepared by reacting an anilino-estercompound of formula (VII) or an anilino-thioester compound of formula(VIII) with hydrazine by conventional procedures, as depicted below:##STR7## wherein R³ and Ar have the same significance as prevouslydefined.

The thiadiazole intermediate of formula (II) (Y═S) is prepared by thefollowing sequence of reactions: ##STR8## wherein Ar, R², R³ and n havethe same significance as previously defined.

Reaction (7) is conducted by reacting substantially equimolar amounts ofthe hydrazide (IV) and the anhydride (IX) in the liquid phase in aninert diluent at a temperature of about 25° C. to 100° C. Reaction (8)is conducted by reacting substantially equimolar amounts of thebis-acylated hydrazine (X) and phosphorus pentasulfide in the liquidphase in the inert diluent at a temperature of 50° C. to 150° C.Reaction (8) is preferably conducted in a basic organic solvent such aspyridine and methyl-substituted pyridines.

The triazole intermediates of formula (II) wherein R² is alkylthio,alkenylthio or alkynylthio are prepared by the following sequence ofreactions: ##STR9## wherein R³, and n have the same significance aspreviously defined, and R and R⁵ are alkyl, alkenyl or alkynyl aspreviously defined.

Reaction (9) comprises reacting a hydrazide (IV) and an isothiocyanate(XI) to form the semithiocarbazide (XII) by conventional procedures.Reaction (10) comprises the cyclization of the semithiocarbazide (XII)in the presence of a base. Reaction (10) is generally conducted byreacting substantially equimolar amounts of the semithiocarbazide (XII)and a strong inorganic base, e.g., alkali metal hydroxides such assodium hydroxide or potassium hydroxide, in an alkanol reaction medium,e.g., methanol or ethanol, at a temperature of 50° C. to 100° C.Reaction (11) comprises the alkylation of the mercapto-substitutedtriazole product (XIII) with the iodo compound (XIV) by conventionalprocedures.

The oxadiazole intermediates of formula (II) wherein R² is alkylthio,alkenylthio or alkynylthio are prepared by the following reaction:##STR10## wherein R³ and n have the same significance as previouslydefined, and R⁵ is alkyl, alkenyl or alkynyl as previously defined.

Reaction (12) comprises the cyclization of the hydrazide (IV) withcarbon disulfide in the presence of a base to give themercapto-substituted oxadiazole (XVI). Reaction (13) comprises thealkylation of the mercapto-substituted oxadiazole (XVI) with theiodoalkane (XIV) by conventional procedures. Reaction (12) is generallyconducted by reacting substantially equimolar amounts of the hydrazide(IV), carbon disulfide and a strong inorganic base, e.g., alkali metalhydroxides, in an alkanol solvent, e.g., methanol or ethanol, at atemperature of 25° to 100° C. An excess of carbon disulfide can be used,if desired. For example, the molar ratio of hydrazide (IV) to carbondisulfide varies from 1.5:1 to 1:1.

The oxadiazole intermediate of formula (II) can also be prepared by thefollowing reaction: ##STR11## wherein Ar, R², R³, R⁴ and n have the samemeaning as previously defined.

Reaction (14) comprises the reaction of the hydrazide (IV) with anortho-ester (XVIII) in the liquid phase at elevated temperatures, e.g.,50°-200° C. Reaction (14) is conducted in a basic solvent, e.g.,pyridine and alkylated-pyridines such as collidine and lutidine.Generally, the molar ratio of hydrazide (IV) to otho-ester (XVIII) issubstantially equimolar, e.g., the molar ratio of hydrazide toortho-ester varies from 1.2:1 to 1:1.2. In reaction (15), the imidateproduct (IX) is cyclized by heating in a basic organic solvent, e.g.,trialkylamines and N,N-dialkylanilines at elevated temperatures, e.g.,100°-250° C. The oxadiazole product (II) is isolated and purified byconventional procedures.

EXAMPLES Example 1--Preparation ofalpha-(2,6-dimethylphenylamino)acethydrazide

A solution of 100 g (0.48 mol) methylalpha-(N-2,6-dimethylphenylamino)thioacetate in 50 ml methanol was addeddropwise to a stirred solution of 27 g (0.72 mol) hydrazine hydrate(85%) in 200 ml methanol at 25° C. The resulting reaction mixture wasstirred at 25° C. for about 16 hours and then evaporated under reducedpressure at 46° C. to give an oil residue. The residue was dissolved in500 ml dichloromethane, washed with 100 ml water and dried overmagnesium sulfate. The dichloromethane was then removed by evaporationunder reduced pressure and the resulting oil crystallized from ethylether to give the crude alpha-(2,6-dimethylphenylamino)acethydrazide.The crude acethydrazide product was washed successively with 100 mlportions of 50% ethyl ether in petroleum ether, 75% ethyl ether inpetroleum ether, and ethyl ether and then air dried to give 65.5 g ofpurified product, m.p. 86°-88° C.

Example 2--Preparation of2-(2,6-dimethylphenylaminomethyl)-5-methyl-1,3,4-oxadiazole)

A solution of 19.3 g (0.1 mol)alpha-(2,6-dimethylphenyl-amino)acethydrazide and 14 g (0.11 mol) ethylactimidate hydrochloride (Aldrich Chemical Co.) in 150 ml pyridine washeated under reflux for 9 hours. The reaction mixture was filtered andthe filtrate was evaporated under reduced pressure to give an oil. Theoil was placed on 400 g silica gel in a chromatography column and elutedthe following solvent systems: (1) petroleum ether, (2) petroleumether/ethyl ether, (3) ethyl ether, and (4) ethyl ether/methanol. Thecrude product (11.5 g) was eluted from the column with the ethylether/methanol solvent system. Crystallization of the crude product fromdichloromethane/ethyl ether gave 7.4 g of crystalline product, m.p.134°-135° C. The product is tabulated in Table I as Compound No. 1-A.

Example 3--Preparation ofN-(5-methyl-1,3,4-oxadiazol-2-ylmethyl)-2,6-dimethyl-alpha-chloroacetanilide

A solution of 1.9 g (0.0166 mol) chloroacetyl chloride in ethyl acetatewas added dropwise to a stirred solution of 3.6 g (0.0166 mol)2-((2,6-dimethylphenylaminomethyl)-5-methyl-1,3,4-oxadiazole and 1.3 g(0.0166 mol) pyridine in 100 ml ethyl acetate at 25° C. The resultingreaction mixture was stirred at 25° C. for 18 hours. Thin-layerchromatography showed the presence of small amounts of unreacted2-(2,6-dimethylphenylaminomethyl)-5-methyl-1,3,4-oxadiazole in thereaction mixture. An 0.3-g sample of pyridine and 0.4 g samplechloroacetyl chloride were then added to the reaction mixture. Thereaction mixture was stirred another 3 hours at 25° C. and diluted with100 ml water. The organic layer was separated, washed with water,saturated aqueous sodium bicarbonate, dried over magnesium sulfate andevaporated under reduced pressure to give a solid. The solid was washedwith ethyl ether/petroleum ether at 0° C. and dried to give 3.7 g ofcolorless product, m.p. 109°-111° C. The product and its elementalanalysis are tabulated in Table I, as Compound No. 1-B.

Example 4--Preparation of3-(2,6-dimethylphenylaminomethyl)-5-methyl-1,2,4-triazole

To a stirred solution of 8.8 g (0.022 mol) sodium hydroxide in 500 mlmethanol was added 20 g (0.22 mol) acetamidine hydrochloride. Afterstirring for an additional 1/4 hour, 37.7 g (0.2 mol)alpha-(2,6-dimethylphenylamino)acethydrazide was added. The reactionmixture was heated under reflux for about 18 hours, cooled and filtered.The filtrate was evaporated under a reduced pressure to give a solidresidue. The residue was diluted with dichloromethane, filtered, driedover magnesium sulfate and evaporated under reduced pressure to give asolid residue, which was triturated with ethyl ether/petroleum ether anddried to give 34.3 g of the product, m.p. 125°-126° C. The product istabulated in Table I as Compound No. 2-A.

Example 5--Preparation ofN-(5-methyl-1,2,4-triazol-3-ylmethyl)-2,6-dimethyl-alpha-chloroacetanilide

A solution of 5 g (0.044 mol) chloroacetyl chloride in 2 ml toluene wasadded dropwise over a one-hour period to a stirred solution of 8.7 g(0.04 mol) 3-(2,6-dimethylphenylaminomethyl)-5-methyl-1,2,4-triazole and4.5 g (0.044 mol) triethylamine at 78°-96° C. The resulting reactionmixture was maintained at 80°-85° C. for another 3 hours and thenallowed to cool to about 25° C. overnight. The reaction mixture wasdiluted with water. The precipitated product was filtered, washed withwater and dissolved in dichloromethane. The dichloromethane solution wasdried over magnesium sulfate, treated with charcoal, filtered andevaporated under reduced pressure to give a colorless solid. Triturationof the solid with cold ethyl ether gave 5.1 g of the product, as acolorless solid, m.p. 178°-179° C. The product and its elementalanalysis are tabulated in Table I, as Compound No. 2B.

Example 6--Preparation of 1-[alpha-(2,6-dimethylphenylamino)acetyl]-4-methylsemithiocarbazide

A solution of 24.8 g (0.339 mol) methyl isothiocyanate in 75 mldichloromethane was added dropwise to a solution of 65.5 g (0.339 mol)alpha-(2,6-dimethylphenylamino)acetic acid hydrazide in 450 mldichloromethane over a period of 1.25 hours at about 25° C. The reactionmixture was heated under reflux for one hour, during which time theproduct precipitated. The reaction mixture was cooled, and the productfiltered, washed successively with dichloromethane and diethylether, anddried in vacuuo at 40°-50° C. The product melted at 173°-174° C.Elemental analysis for C₁₂ H₁₈ N₄ OS showed:

    ______________________________________                                                  Calc.       Found                                                   ______________________________________                                        %C          54.1          52.6                                                %H          6.8           6.9                                                 %N          21.0          20.5                                                ______________________________________                                    

Example 7--Preparation of3-(2,6-dimethylphenylaminomethyl)-4-methyl-5-mercapto-1,2,4-triazole

To a stirred hot solution of 52.8 g (0.198 mol)1[alpha-(2,6-dimethylphenylamino)acetyl]-4-methylthiosemicarbazide in560 ml ethanol was added quickly 8 g (0.198 mol) sodium hydroxide. Thereaction mixture was heated under reflux for 2 hours and allowed tostand overnight. The ethanol was then evaporated under reduced pressureto give a solid residue. Water (500 ml) was added to the solid residueand the resulting aqueous mixture was filtered to remove a small amountof a solid. The filtrate was neutralized with concentrated hydrochloricacid, the colorless solid was filtered, washed with water and partiallydried in vacuuo over potassium hydroxide pellets at 50° C. The nearlydried product was dissolved in dichloromethane and the aqueous layerseparated. The organic layer was dried over magnesium sulfate, filteredand evaporated under reduced pressure to give 43.5 g of the product as acolorless solid, m.p. 172°-173° C. The product is tabulated in Table Ias Compound No. 3.

Example 8--Preparation of(3-(2,6-dimethylphenylaminomethyl)-4-methyl-5-methylthio-1,2,4-triazole

To a stirred solution of 1.7 g (0.0419 mol) sodium hydroxide is 125 mlwater was added in one portion, 10.4 g (0.0419 mol),3-(2,6-dimethylphenylaminomethyl)-4-methyl-5-mercapto-1,2,4-triazole.After a homogeneous solution was obtained, 6.2 g (0.044 mol) methyliodide was added dropwise. The reaction mixture was then diluted with 50ml dichloromethane and vigorously stirred for 0.5 hour. The reactionmixture was diluted with another 100 ml dichloromethane and the organiclayer was separated, dried over magnesium sulfate, filtered andevaporated under reduced pressure to give a solid residue. The solid wastriturated with ethyl ether to give the product as a colorless solid.The product is tabulated in Table I as Compound No. 14-A.

Example 9--Preparation of3-(N-chloroacetyl-2,6-dimethylphenylamino)-4-methyl-5-methylthio-1,2,4-triazole

To a stirred solution of 6.1 g (0.0232 mol)3-(2,6-dimethylphenylamino)-4-methyl-5-methylthio-1,2,4-triazole in 150ml toluene was added quickly 2.7 g (0.024 mol) chloroacetyl chloride. Anexotherm ensued and the temperature rose to 100° C., followed byseparation of an oil which solidified. The reaction mixture was stirredat 100°-105° C. for 1 hour, cooled and diluted with 50 ml saturatedsodium bicarbonate and 20 ml dichloromethane. The clear organic layerwas separated, dried over magnesium sulfate and evaporated under reducedpressure to give a clear oil. The oil was crystallized from ethyl etherto give 7.4 g of product, as a pale yellow solid, m.p. 145°-147° C. Theproduct is tabulated in Table I as Compound No. 14-B.

Example 10--Preparation of2-(2,6-dimethylphenylaminomethyl)-5-methyl-1,3,4-thiadiazole

To a stirred solution of 19.9 g (0.103 mol)alpha-(2,6-dimethylphenylamino)acethydrazide in 350 ml dichloromethanewas added quickly 11.3 g (0.103 mol) acetic anhydride. A mild exothermensued. After being stirred at about 25° C. for about 16 hours, thereaction mixture was filtered to give 8.9 g of1-(2,6-dimethylphenylaminoacetyl)-2-acetyl hydrazine, m.p. 148°-150° C.

To a stirred solution of 16.0 g (0.068 mol)1-(2,6-dimethylphenylaminoacetyl)-2-acetylhydrazine in 150 ml pyridinewas added 15.1 g (0.068 mol) phosphorus pentasulfide in small portions.A mild exotherm ensued. The reaction mixture was heated to 140°-150° C.when an exotherm ensued. The reaction temperature rose to 170° C., andthen subsided. Hydrogen sulfide was liberated. The reaction was kept at140°-150° C. for 2 hours and then at 25° C. for about 16 hours. Thepyridine solution was decanted from a gummy brown residue. The residuewas extracted with dichloromethane. The dichloromethane extracts werecombined with the pyridine solution and evaporated under reducedpressure to give an oil. The oil was dissolved in dichloromethane andtreated with ice water to destroy a small amount of unreacted phosphoruspentasulfide. The dichloromethane solution was then washed with colddilute aqueous sodium hydroxide solution, water, dried over magnesiumsulfate, filtered and evaporated under reduced pressure at 40°-50° C. togive an oil. The oil was column chromatographed on 200 g silica gelusing petroleum ether/diethyl ether as eluants. The major fractions werecombined in dichloromethane, dried over magnesium sulfate, filtered andevaporated under reduced pressure to give a clear oil which crystallizedupon trituration with petroleum ether to give 11.6 g of2-(2,6-dimethylphenylaminomethyl)-5-methyl-1,3,4-thiadiazole, m.p.68°-69° C. The product is tabulated in Table I as Compound No. 29A.

Example 11--Preparation ofN-(5-methyl-1,3,4-thiadiazol-2-yl-methyl)-2,6-dimethyl-alpha-chloroacetanilide

To a stirred solution of 4 g (0.0171 mol)2-(2,6-dimethylphenylaminomethyl)-5-methyl-1,3,4-thiadiazole and 1.4 g(0.018 mol) pyridine in 100 ml benzene heated to 85° C. was addedquickly 2.0 g (0.018 mol) chloroacetyl chloride. A mild exotherm ensued,accompanied by separation of a solid. The reaction mixture was kept at90°-95° C. for 2 hours, cooled and diluted with water. The organic layerwas separated, washed with aqueous sodium bicarbonate solution, driedover magnesium sulfate, filtered and evaporated under reduced pressureto give an oil, which crystallized to give 3.9 g of the product, as acolorless crystalline solid, m.p. 117°-118° C. The product is tabulatedin Table I as Compound No. 29-B.

Example 12--Preparation of2-(2,6-dimethylphenylaminomethyl)-5-mercapto-1,3,4-oxadiazole

A 58.0-g (0.3 mol) sample ofalpha-(2,6-dimethylphenylamino)acethydrazide was added to a solution of19.8 g (0.3 mol) potassium hydroxide in 500 ml ethanol. A solution of26.3 g of (0.34 mol) carbon disulfide in 30 ml ethanol was addeddropwise over a 45-minute period. A mild exotherm ensued, followed bythe separation of a solid. After the addition was completed, thereaction mixture was diluted with ethanol and heated under reflux forabout 14 hours until hydrogen sulfide evolution ceased. The reactionmixture was then cooled and filtered to remove an unidentified solidby-product. The filtrate was evaporated under reduced pressure at 46° C.to give an oil. The oil was dissolved in dichloromethane, extractedsuccessively with water, aqueous sodium hydroxide solution and water.The aqueous extracts were combined, cooled to 0° C. and acidified withconcentrated hydrochloric acid, causing a solid to crystallize. Thesolid was filtered, washed with water, dissolved in dichloromethane,dried over magnesium sulfate, filtered and evaporated under reducedpressure to give a solid residue. Trituration with ethyl ether/petroleumether at 0° C. gave the product as a pale yellow powder, m.p. 115°-117°C.

Example 13--Preparation of2-(2,6-dimethylphenylaminomethyl)-5-methylthio-1,3,4-oxadiazole

To a stirred mixture of 16.2 g (0.0688 mol)2-(2,6-dimethylphenylaminomethyl)-5-mercapto-1,3,4-oxadiazole in 200 mlwater and 200 ml dichloromethane was added quickly 2.8 g (0.0688 mol)sodium hydroxide. To the resulting reaction mixture was then added 9.9 g(0.0688 mol) iodomethane. The reaction mixture was stirred at about 25°C. for 1 hour and then heated under reflux for 1 hour. After thereaction mixture was allowed to stand overnight at 25° C., the organiclayer was separated, dried over magnesium sulfate, filtered andevaporated under reduced pressure to give a yellow solid. Triturationwith ethyl ether/petroleum ether gave 8.8 g of2-(2,6-dimethylphenylaminomethyl)-5-methylthio-1,3,4-oxadiazole, m.p.84°-85° C. The product is tabulated in Table I as Compound No. 24-A.

Chloroacetylation of the product gaveN-(5-methylthio-1,3,4-oxathiazol-2-yl-methyl)-2,6-dimethyl-alpha-chloroacetanilide,which is tabulated in Table I as Compound No. 24-B.

Example 14--Preparation of2-(2,6-dimethylphenylaminomethyl)-5-methyl-1,3,4-oxadiazole

A stirred solution of 11.0 g (0.05 mol)alpha-(2,6-diethylphenylamino)acethydrazide, 7.2 g (0.06 mol) trimethylorthoacetate and 150 ml 2,6-dimethyllutidine was heated at 125°-130° C.for 16.5 hours and then at 150° C. for 22 hours. The reaction mixturewas then evaporated under reduced pressure at 50°-60° C. to give an oilwhich crystallized to give a solid product, m.p. 109°-110° C. Infrared(carbonyl at 1630 cm⁻¹) and nuclear magnetic analysis showed thefollowing imidate structure for the product: ##STR12##

The imidate product was dissolved in 100 ml N,N-dimethylaniline andheated under a Dean Stark water separator at a temperature of 200°-240°C. for a period of 1.5 hours. Methanol was collected in the separator.The reaction mixture was allowed to cool to about 25° C., stirredovernight, and evaporated under reduced pressure at 62° C. to give anoil. The oil was chromatographed on silica gel (300 g). Elution withethyl ether gave 10.3 g of the desired product as a colorless oil.Elemental analysis for C₁₄ H₁₉ N₃₀ showed: %C, calc. 68.5, found 68.4;%H, calc. 7.8, found 7.9.

The compounds tabulated in Table I were prepared by procedures similarto those of Examples 1-14. The structure of each compound tabulated inTable I was confirmed by nuclear magnetic resonance and/or infraredspectroscopy.

UTILITY

The compounds of the present invention are, in general, herbicidal inboth pre- and post-emergent applications. For pre-emergent control ofundesirable vegetation, the herbicidal compounds will be applied inherbicidally effective amounts to the locus or growth medium of thevegetation, e.g., soil infested with seeds and/or seedlings of suchvegetation. Such application will inhibit the growth of or kill theseeds, germinating seeds and seedlings. For post-emergent applications,the herbicidal compounds will be applied directly to the foliage andother plant parts. Generally, the herbicidal compounds of the inventionare effective against weed grasses as well as broadleaved weeds. Somemay be selective with respect to the type of application and/or type ofweed.

The compounds of the present invention can be used alone as herbicides.However, it is generally desirable to apply the compounds in herbicidalcompositions comprising one or more of the herbicidal compoundsintimately admixed with a biologically inert carrier. The carrier may bea liquid diluent or a solid, e.g., in the form of dust powder orgranules. In the herbicidal composition, the active herbicidal compoundscan be from about 0.01 to 95% by weight of the entire composition.

Suitable liquid diluent carriers include water and organic solvents,e.g., hydrocarbons such as benzene, toluene, kerosene, diesel oil, fueloil, and petroleum naphtha. Suitable solid carriers are natural clayssuch as kaolinite, atalpulgite, and montmorillonite. In addition, talcs,pyrophillite, diatomaceous silica, synthetic fine silicas, calciumaluminosilicate and tricalcium phosphate are suitable carriers. Organicmaterials such as walnut-shell flour, cottonseed hulls, wheat flour,wood flour or redwood-bark flour may also be used as solid carriers.

The herbicidal composition will also usually contain a minor amount of asurface-active agent. Such surface agents are those commonly known aswetting agents, dispersing agents and emulsifying agents, and can beanionic, cationic or nonionic in character. The herbicidal compositionsmay also contain other pesticides, adjuvants, stabilizers, conditioners,fillers, and the like.

The amount of herbicidal compound or composition administered will varywith the particular plant part or plant growth medium which is to becontacted, the general location of application--i.e., sheltered areassuch as greenhouses, as compared to exposed areas such as fields--aswell as the desired type of control. Generally, for both pre- andpost-emergent control, the herbicidal compounds of the invention areapplied at rates of 0.2 to 60 kg/ha, and the preferred rate is in therange 0.5 to 40 kg/ha.

Pre- and post-emergent herbicidal tests on representative compounds ofthe invention were made using the following methods:

Pre-Emergent Test

An acetone solution of the test compound was prepared by mixing 750 mgof the compound, 220 mg of a nonionic surfactant and 25 ml of acetone.This solution was added to approximately 125 ml of water containing 156mg of surfactant.

Seeds of the test vegetation were planted in a pot of soil and the testsolution was sprayed uniformly onto the soil surface at a dose of 33micrograms/cm². The pot was watered and placed in a greenhouse. The potwas watered intermittently and was observed for seedling emergence,health of emerging seedlings, etc., for a 3-week period. At the end ofthis period, the herbicidal effectiveness of the compound was ratedbased on the physiological observations. A 0-to-100 scale was used, 0representing no phytotoxicity, 100 representing complete kill. Theresults of these tests appear in Table II.

Post-Emergent Test

The test compound was formulated in the same manner as described abovefor the pre-emergent test. The concentration of the test compound inthis formulation was 5000 ppm. This formulation was uniformly sprayed on2 similar pots of 24-day-old plants (approximately 15 to 25 plants perpot) at a dose of 33 micrograms/cm². After the plants had dried, theywere placed in a greenhouse and then watered intermittently at theirbases, as needed. The plants were observed periodically for phytotoxiceffects and physiological and morphological responses to the treatment.After 3 weeks, the herbicidal effectiveness of the compound was ratedbased on these observations. A 0-to-100 scale was used, 0 representingno phytotoxicity and 100 representing complete kill. The results ofthese tests appear in Table II.

                                      TABLE I                                     __________________________________________________________________________    Compounds of the formula                                                       ##STR13##                                                                                                             Elemental Analysis                                                            C      H      N (Cl)                 No.                                                                              Ar       Y   R.sup.2  R.sup.3                                                                          n R.sup.5                                                                             m.p., °C.                                                                   Calc.                                                                            Found                                                                             Calc.                                                                            Found                                                                             Calc.                                                                             Found              __________________________________________________________________________     1A                                                                              2,6-(CH.sub.3).sub. 2 φ                                                            O   CH.sub.3 H  1 H     134-135                                                                            66.3                                                                             66.9                                                                              7.0                                                                              7.2 19.3                                                                              21.1                1B                                                                              2,6-(CH.sub.3).sub.2 φ                                                             O   CH.sub.3 H  1 COCH.sub.2 Cl                                                                       109-111            (12.1)                                                                            (11.7)              2A                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NH  CH.sub.3 H  1 H     125-126                                                                            66.6                                                                             66.5                                                                              7.5                                                                              7.5 25.9                                                                              26.7                2B                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NH  CH.sub.3 H  1 COCH.sub.2 Cl                                                                       178-179            (12.11)                                                                           (12.2)              3 2,6-(CH.sub.3).sub.2 φ                                                             NCH.sub.3                                                                         SH       H  1 H     172-173                                                                            58.0                                                                             57.5                                                                              6.5                                                                              6.6 22.6                                                                              22.6                4 2-CH.sub.3 -6-C.sub.2 H.sub.5 -φ                                                   O   CH.sub.3 H  l COCH.sub.2 Cl                                                                       64-65              (11.5)                                                                            (11.6)              5A                                                                              2,6-(C.sub.2 H.sub.5).sub.2 -φ                                                     NH  CH.sub.3 H  1 H     78-80                                                                              68.8                                                                             69.3                                                                              8.3                                                                              8.6 22.9                                                                              23.1                5B                                                                              2,6-(C.sub.2 H.sub.5).sub.2 -φ                                                     NH  CH.sub.3 H  1 COCH.sub.2 Cl                                                                       170-171                                                                            59.9                                                                             60.1                                                                              5.6                                                                              6.6 17.5                                                                              18.5                6A                                                                              2-CH.sub.3 -6-C.sub.2 H.sub.5 -φ                                                   NH  CH.sub.3 H  1 H     81-82                                                                              67.2                                                                             67.6                                                                              7.9                                                                              7.9 24.3                                                                              24.5                6B                                                                              2-CH.sub.3 -6-C.sub.2 H.sub.5 -φ                                                   NH  CH.sub.3 H  1 COCH.sub.2 Cl                                                                       150-154                                                                            58.7                                                                             60.9                                                                              6.2                                                                              6.6 18.3                                                                              19.2                7A                                                                              2-(CH.sub.3).sub.2 φ                                                               NH  C.sub.2 H.sub.5                                                                        H  1 H     93-95                                                                              67.8                                                                             67.7                                                                              7.9                                                                              8.0 24.3                                                                              24.0                7B                                                                              2-(CH.sub.3).sub.2 φ                                                               NH  C.sub.2 H.sub.5                                                                        H  1 COCH.sub.2 Cl                                                                       137-141                                                                            58.7                                                                             58.8                                                                              6.2                                                                              6.3 18.3                                                                              18.5                8A                                                                              2,6-(C.sub.2 H.sub.5).sub.2 φ                                                      NH  C.sub.2 H.sub.5                                                                        H  1 H     55-60                                                                              69.8                                                                             67.2                                                                              8.6                                                                              8.4 21.7                                                                              21.2                8B                                                                              2,6-(C.sub.2 H.sub.5).sub.2 -φ                                                     NH  C.sub.2 H.sub.5                                                                        H  1 COCH.sub.2 Cl                                                                       112-114                                                                            61.2                                                                             57.8                                                                              6.6                                                                              6.6 16.8                                                                              16.5                9A                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NH  H        H  1 H     149-151                                                                            65.3                                                                             62. 7.0                                                                              6.8 22.7                                                                              25.3                9B                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NH  H        H  1 COCH.sub.2 Cl                                                                       172-174                                                                            56.1                                                                             54.9                                                                              5.4                                                                              5.5 20.1                                                                              19.4               10A                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NH  CH.sub.3 H  2 H     75-76                                                                              67.8                                                                             66.1                                                                              7.9                                                                              8.0 24.3                                                                              23.6               10B                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NH  CH.sub.3 H  2 COCH.sub.2 Cl                                                                       135-137                                                                            58.7                                                                             58.4                                                                              6.2                                                                              6.3 18.3                                                                              18.1               11A                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NH  CH.sub.3 CH.sub.3                                                                         1 H     106-108                                                                            67.7                                                                             68.8                                                                              7.9                                                                              8.1 24.3                                                                              24.8               11B                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NH  CH.sub.3 CH.sub.3                                                                         1 COCH.sub.2 Cl                                                                       138-139                                                                            58.7                                                                             58.9                                                                              6.2                                                                              6.4 18.4                                                                              18.4               12A                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NH  H        CH.sub.3                                                                         1 H     137-138                                                                            66.6                                                                             66.5                                                                              7.5                                                                              7.5 25.9                                                                              26.1               12B                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NH  H        CH.sub.3                                                                         1 COCH.sub.2 Cl                                                                       149-150                                                                            57.4                                                                             57.2                                                                              5.9                                                                              5.9 19.1                                                                              19.0               13 2,6-(CH.sub.3).sub.2 φ                                                             NH  H        H  2 COCH.sub.2 Cl                                                                       119-125                                                                            57.4                                                                             56.5                                                                              5.9                                                                              6.0 19.1                                                                              18.1               14A                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NCH.sub.3                                                                         SCH.sub.3                                                                              H  1 H     101-102                                                                            54.5                                                                             55.7                                                                              6.9                                                                              7.1 21.4                                                                              20.6               14B                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NCH.sub.3                                                                         SCH.sub.3                                                                              H  1 COCH.sub.2 Cl                                                                       145-147                                                                            53.2                                                                             53.9                                                                              5.7                                                                              5.8 16.5                                                                              16.9               15A                                                                              2-CH.sub.3 -6-C.sub.2 H.sub.5 -φ                                                   NH  C.sub.2 H.sub.5                                                                        H  1 H     69-74                                                                              68.8                                                                             68.3                                                                              8.3                                                                              8.4 22.4                                                                              20.8               15B                                                                              2-CH.sub.3 -6-C.sub.2 H.sub.5 -φ                                                   NH  C.sub.2 H.sub.5                                                                        H  1 COCH.sub.2 Cl                                                                       101-105                                                                            59.9                                                                             57.8                                                                              6.6                                                                              6.9 17.5                                                                              15.9               16A                                                                              2-CH.sub.3 -6-C.sub.2 H.sub.5 -φ                                                   NH  i-C.sub.3 H.sub.7                                                                      H  1 H     89-90                                                                              69.7                                                                             69.5                                                                              8.6                                                                              8.4 21.9                                                                              20.9               16B                                                                              2-CH.sub.3 -6-C.sub.2 H.sub.5 -φ                                                   NH  i-C.sub.3 H.sub.7                                                                      H  1 COCH.sub.2 Cl                                                                       83-85                                                                              61.0                                                                             60.8                                                                              6.9                                                                              6.9 16.7                                                                              16.7               17A                                                                              2-CH.sub.3 -6-C.sub.2 H.sub.5 -φ                                                   NH  H        H  1 H     122-124                                                                            66.6                                                                             66.6                                                                              7.5                                                                              7.6 26.0                                                                              26.4               17B                                                                              2-CH.sub.3 -6-C.sub.2 H.sub.5 -φ                                                   NH  H        H  1 COCH.sub.2 Cl                                                                       153-155                                                                            57.4                                                                             53.8                                                                              5.9                                                                              5.8 19.1                                                                              17.7               18A                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NH  SH       H  1 H     224-225                                                                            56.4                                                                             55.9                                                                              6.0                                                                              6.0 23.9                                                                              23.8               18B                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NH  SH       H  1 COCH.sub.2 Cl                                                                       135-137                                                                            51.8                                                                             54.7                                                                              5.3                                                                              5.4 17.3                                                                              17.4               19 2-CH.sub.3 -6-C.sub.2 H.sub.5 -φ                                                   NCH.sub.3                                                                         SH       H  1 H     139-141                                                                            59.5                                                                             59.3                                                                              6.9                                                                              6.9 21.4                                                                              21.9               20A                                                                              2,6-(C.sub.2 H.sub.5).sub.2 -φ                                                     NH  H        H  1 H     160-161                                                                            67.8                                                                             67.7                                                                              7.9                                                                              8.0 24.3                                                                              25.0               20B                                                                              2,6-(C.sub.2 H.sub.5).sub.2 -φ                                                     NH  H        H  1 COCH.sub.2 Cl                                                                       160-162                                                                            58.7                                                                             57.0                                                                              6.2                                                                              6.2 18.3                                                                              17.8               21A                                                                              2-CH.sub.3 -6-C.sub.2 H.sub.5 -φ                                                   NCH.sub.3                                                                         SCH.sub.3                                                                              H  1 H     93-95              11.6(S)                                                                           12.0               21B                                                                              2-CH.sub.3 -6-C.sub.2 H.sub.5 -φ                                                   NCH.sub.3                                                                         SCH.sub.3                                                                              H  1 COCH.sub.2 Cl                                                                       92-96                                                                              54.5                                                                             56.3                                                                              6.0                                                                              6.3 15.9                                                                              17.3               22A                                                                              2-Cl-6-CH.sub.3 -φ                                                                 NH  CH.sub.3 H  1 H     127-128                                                                            56.3                                                                             54.4                                                                              4.7                                                                              5.8 23.9                                                                              25.1               22B                                                                              2-Cl-6-CH.sub.3 -φ                                                                 NH  CH.sub.3 H  1 COCH.sub.2 Cl                                                                       162-163                                                                            40.9                                                                             49.8                                                                              4.5                                                                              4.4 17.9                                                                              18.7               23A                                                                              2,6-(C.sub.2 H.sub.5).sub.2 -φ                                                     NCH.sub.3                                                                         SCH.sub.3                                                                              H  1 H     80-81                                                                              62.0                                                                             61.9                                                                              7.6                                                                              7.9 19.3                                                                              20.7               23B                                                                              2,6-(C.sub.2 H.sub.5).sub.2 -φ                                                     NCH.sub.3                                                                         SCH.sub.3                                                                              H  1 COCH.sub.2 Cl                                                                       125-126                                                                            55.7                                                                             56.9                                                                              6.8                                                                              6.6 15.2                                                                              16.1               24A                                                                              2,6-(CH.sub.3).sub.2 φ                                                             O   SCH.sub.3                                                                              H  1 H     84-85                                                                              57.8                                                                             57.5                                                                              6.1                                                                              6.2 16.9                                                                              17.3               24B                                                                              2,6-(CH.sub.3).sub.2 φ                                                             O   SCH.sub.3                                                                              H  1 COCH.sub.2 Cl                                                                       111-115                                                                            51.6                                                                             52.8                                                                              5.0                                                                              5.2 12.9                                                                              13.8               25A                                                                              2-CH.sub.3 -φ                                                                      NH  CH.sub.3 H  1 H     117-118                                                                            65.3                                                                             62.6                                                                              7.0                                                                              7.4 27.7                                                                              32.2               25B                                                                              2-CH.sub.3 -φ                                                                      NH  CH.sub.3 H  1 COCH.sub.2 Cl                                                                       118-122                                                                            56.0                                                                             55.7                                                                              5.4                                                                              5.6 20.1                                                                              20.5               26A                                                                              3-CF.sub.3 -φ                                                                      NH  CH.sub.3 H  1 H     128-129                                                                            51.6                                                                             52.6                                                                              4.3                                                                              4.5 21.8                                                                              23.6               26B                                                                              3-CF.sub.3 -φ                                                                      NH  CH.sub.3 H  1 COCH.sub.2 Cl                                                                       111-113                                                                            46.9                                                                             47.9                                                                              3.6                                                                              3.9 16.8                                                                              17.9               27A                                                                              3,4-Cl.sub.2 -φ                                                                    NH  CH.sub.3 H  1 H     144-145                                                                            46.7                                                                             47.6                                                                              3.9                                                                              4.2 21.8                                                                              23.3               27B                                                                              3,4-Cl.sub.2 -φ                                                                    NH  CH.sub.3 H  1 COCH.sub.2 Cl                                                                       53-63                                                                              43.2                                                                             41.8                                                                              3.3                                                                              3.7 16.8                                                                              17.0               28 2-CH.sub.3 -6-C.sub.2 H.sub.5 -φ                                                   NH  CH.sub.2 CHCH.sub.2 *                                                                  H  1 COCH.sub.2 Cl                                                                       119-120                                                                            61.4                                                                             61.8                                                                              6.4                                                                              6.5 16.8                                                                              17.8               29A                                                                              2,6-(CH.sub.3).sub.2 φ                                                             S   CH.sub.3 H  1 H     68-69                                                                              61.8                                                                             62.4                                                                              6.5                                                                              6.7 18.0                                                                              18.9               29B                                                                              2,6-(CH.sub.3).sub.2 φ                                                             S   CH.sub.3 H  1 COCH.sub.2 Cl                                                                       117-118                                                                            54.3                                                                             54.9                                                                              5.2                                                                              5.4 13.6                                                                              14.0               30 2,6-(C.sub.2 H.sub.5 ).sub.2 -φ                                                    NH  CH.sub.2 CHCH.sub.2                                                                    H  1 COCH.sub.2 Cl                                                                       123-124                                                                            62.32                                                                            63.63                                                                             6.7                                                                              6.8 16.2                                                                              18.6               31 2,6-(CH.sub.3).sub.2 φ                                                             NH  CH.sub.2 CHCH.sub.2                                                                    H  1 COCH.sub.2 Cl                                                                       144-146                                                                            60.3                                                                             60.1                                                                              6.0                                                                              6.2 17.6                                                                              18.6               32 2,6-(CH.sub.3).sub.2 φ                                                             NCH.sub.3                                                                         S-i-C.sub.3 H.sub.7                                                                    H  1 COCH.sub.2 Cl                                                                       99-100                                                                             55.7                                                                             55.9                                                                              6.3                                                                              6.3 15.3                                                                              15.9               33A                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NH  n-C.sub.5 H.sub.11                                                                     H  1 H     110-111                                                                            70.6                                                                             72.1                                                                              8.9                                                                              9.1 20.6                                                                              21.6               33B                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NH  n-C.sub.5 H.sub.11                                                                     H  1 COCH.sub.2 Cl                                                                       102-103                                                                            62.0                                                                             59.6                                                                              7.2                                                                              6.9 16.1                                                                              16.2               34A                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NCH.sub.3                                                                         SCH.sub.2 CCH                                                                          H  1 H     106-107                                                                            62.9                                                                             62.6                                                                              6.3                                                                              6.5 19.6                                                                              20.1               34B                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NCH.sub.3                                                                         SCH.sub.2 CCH                                                                          H  1 COCH.sub.2 Cl                                                                       78-80                                                                              56.3                                                                             56.7                                                                              5.2                                                                              5.4 15.4                                                                              16.0               35 2,6-(CH.sub.3).sub.2 φ                                                             NCH.sub.3                                                                         SCH.sub.2 CCH.sub.2                                                                    H  1 COCH.sub.2 Cl                                                                       95-97                                                                              56.0                                                                             56.3                                                                              5.8                                                                              6.0 15.4                                                                              15.8               36A                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NH  φ    H  1 H          73.4                                                                             73.6                                                                              6.5                                                                              7.1 20.1                                                                              19.9               36B                                                                              2,6-(CH.sub.3).sub.2 φ                                                             NH  φ    H  1 COCH.sub.2 Cl                                                                       122-127                                                                            64.3                                                                             64.4                                                                              5.4                                                                              5.7 15.8                                                                              16.2               __________________________________________________________________________     φrepresents phenyl                                                        *CH.sub.2 CHCH.sub.2 and CHCHCH.sub.3 mixture                            

                  TABLE II                                                        ______________________________________                                        Herbicidal Effectiveness                                                      % Control Pre/Post.sup.1                                                      No.   L        M         P     C     W     O                                  ______________________________________                                         1A   0/0      0/0       0/0   0/0   0/0   0/0                                 1B   50/0     45/0      87/0  100/0 100/0 90/0                                2A   0/0      0/0       0/0   0/0   0/0   0/0                                 2B   98/50    75/25     88/32 100/20                                                                              100/75                                                                              100/30                              3    0/0      0/0       0/0   0/0   0/0   0/0                                 4    10/0     10/0      65/0  100/20                                                                              100/60                                                                              93/50                               5A   0/0      0/0       0/0   0/0   0/0   0/0                                 5B.sup.2                                                                           --       --        --    --    100/- --                                  6A   0/0      0/0       0/0   0/0   0/0   0/0                                 6B.sup.2                                                                           --       --        --    --    --    100/--                              7A   0/0      0/0       0/0   0/0   0/0   0/0                                 7B.sup.3                                                                           0/0      0/0       0/0   0/0   0/0   0/0                                 8A   0/0      0/0       0/0   0/0   0/0   0/0                                 8B.sup.2                                                                           100/-    83/-      90/-  100/- 100/- 99/-                                9A   0/0      0/0       0/0   0/0   0/0   0/0                                 9B   100/25   55/25     100/0 100/70                                                                              100/75                                                                              100/65                             10A   0/0      0/0       0/0   0/0   0/0   0/0                                10B    0/25     0/35     0/0   80/40 95/55 15/25                              11A   0/0      0/0       0/0   0/0   0/0   0/0                                11B   100/25   80/20     90/20 100/55                                                                              100/73                                                                              97/10                              12A   0/0      0/0       0/0   0/0   0/0   0/0                                12B   75/45    75/0      90/20 100/65                                                                              100/80                                                                              97/45                              13    75/0     20/0      40/0  85/60 97/63 25/20                              14A   0/0      0/0       0/0   0/0   0/0   0/0                                14B   0/0      0/0       0/0   90/0  100/0 10/0                               15A   0/0      0/0       0/0   0/0   0/0   0/0                                15B   100/35   100/35    100/30                                                                              100/75                                                                              100/80                                                                              100/55                             16A   0/0      0/0       0/0   0/0   0/0   0/0                                16B   100/35   95/40     95/40 100/70                                                                              100/75                                                                              100/70                             17A   0/0      0/0       0/0   0/0   0/0   0/0                                17B   100/65   90/75     95/65 100/75                                                                              100/75                                                                              100/60                             18A   0/0      0/0       0/0   0/0   0/0   0/0                                18B   0/0      0/0       0/0   0/0   0/0   0/0                                19    0/0      0/0       0/0   0/0   0/0   0/0                                20A   0/0      0/0       0/0   0/0   0/0   0/0                                20B   97/25    95/30     100/35                                                                              95/30 100/55                                                                              97/0                               21A   0/0      0/0       0/0   0/0   0/0   0/0                                21B   0/0      0/0       0/0   0/0   98/0  0/0                                22A   0/0      0/0       0/0   0/0   0/0   0/0                                22B   85/20    80/25     93/75 100/0 100/60                                                                              95/0                               23A   0/0      0/0       0/0   0/0   0/0   0/0                                23B   0/0      0/0       0/0   0/0   0/0   0/0                                24A   0/0      0/0       0/0   0/0   0/0   0/0                                24B   10/0     10/0      10/0  100/0 100/0 85/0                               25A   0/0      0/0       0/0   0/0   0/0   0/0                                25B   100/0    45/0      70/0  97/0  100/40                                                                              0/0                                26B   10/0     10/0      0/0   0/0   65/0  0/0                                27A   0/0      0/0       0/0   0/0   0/0   0/0                                27B   0/0      0/0       0/0   0/0   0/0   0/0                                28    100/0    93/0      100/0 100/0 100/0 97/0                               ______________________________________                                         .sup.1 33 micrograms per cm.sup.2                                             .sup.2 11 micrograms per cm.sup.2                                             .sup.3 1.8 micrograms per cm.sup.2                                            L = Lambsquarter (Chenopodium album)                                          M = Mustard (Brassica arvensis)                                               P = Pigweed (Amaranthus retroflexus)                                          C = Crabgrass (Digitaria sanguinalis)                                         W = Watergrass (Echinochloa                                                   O = Wild Oats (Avena fatua)                                              

What is claimed is:
 1. A compound of the formula ##STR14## wherein Ar isphenyl or phenyl substituted with 1 to 3 of the same or differentsubstituents selected from fluoro, chloro, bromo, iodo, alkyl of 1 to 4carbon atoms, alkoxy of 1 to 4 carbon atoms or haloalkyl of 1 to 4carbon atoms and 1 to 3 of the same or different halogens selected fromfluoro, chloro, bromo or iodo, R¹ is halomethyl of 1 to 3 of the same ordifferent halogens selected from fluoro, chloro, bromo, or iodo, R² ishydrogen; alkyl of 1 to 6 carbon atoms; alkenyl of 2 to 6 carbon atoms;alkynyl of 2 to 6 carbon atoms; cycloalkyl of 3 to 6 carbon atoms;haloalkyl of 1 to 4 carbon atoms and 1 to 3 of the same or differenthalogens selecteed from fluoro, chloro, bromo or iodo; alkoxy of 1 to 6carbon atoms; alkylthio of 1 to 6 carbon atoms; alkenylthio of 2 to 6carbon atoms; alkynylthio of 2 to 6 carbon atoms; phenyl; phenylsubstituted with 1 to 3 of the same or different substituents selectedfrom fluoro, chloro, bromo, iodo, alkyl of 1 to 4 carbon atoms, alkoxyof 1 to 4 carbon atoms or haloalkyl of 1 to 4 carbon atoms and of 1 to 3of the same or different halogens selected from fluoro, chloro, bromo oriodo; or NR⁵ R⁶ wherein R⁵ and R⁶ individually are hydrogen, alkyl of 1to 6 carbon atoms, alkenyl of 2 to 6 carbon atoms or alkynyl of 2 to 6carbon atoms, R³ is hydrogen or alkyl of 1 to 6 carbon atoms, n is 1 or2, and Y is NR wherein R is hydrogen, alkyl of 1 to 6 carbon atoms,alkenyl of 2 to 6 carbon atoms or alkynyl of 2 to 6 carbon atoms withthe proviso that Ar is not 3,4-dichlorophenyl.
 2. A compound of theformula defined in claim 1 wherein R¹ is monohalomethyl.
 3. A compoundof the formula defined in claim 1 wherein Ar is 2,6-dialkylphenyl.
 4. Acompound of the formula defined in claim 1 wherein R³ is hydrogen and nis
 1. 5. A compound of the formula defined in claim 1 wherein R² ishydrogen, alkyl, phenyl or phenyl substituted with 1 to 3 fluoro,chloro, bromo or alkyl of 1 to 3 carbon atoms.
 6. A compound of theformula defined in claim 1 wherein Y in NR and wherein R is hydrogen oralkyl.
 7. The compound of claim 1 wherein Ar is 2,6-dialkylphenyl, R¹ ismonohalomethyl, R² is alkyl, R³ is hydrogen, Y is NH and n is
 1. 8. Thecompound of claim 7 wherein Ar is 2-methyl-6-ethylphenyl and R¹ ischloromethyl.
 9. The compound of claim 7 wherein Ar is2,6-dimethylphenyl and R¹ is chloromethyl.
 10. An herbicidal compositioncomprising an herbicidally effective amount of the compound defined inclaim 1 and a biologically inert carrier.
 11. A method for controllingundesirable vegetation which comprises applying to said vegetation orits growth medium an herbicidally effective amount of the compounddefined in claim 1.